Bacteria are single-cell microscopic organisms which are prokaryotes (they lack membrane organelles like the cell nucleus and mitochondria). A basic bacterial cell is made up of a rigid cell wall, followed by a cell membrane and a cytoplasm where ribosomes and genetic material are suspended, some have flagella for locomotion and others don’t, while some have pili. Bacteria are basically found almost everywhere, only they are not visible with naked eyes.
Bacteria reproduction is normally fast when the environment they are in is conducive. It is achieved by both asexual and sexual means. Asexual reproduction takes place with only one cell without a partner involved. There is no exchange of genetic material.
This process, also known as binary fission, normally begins by enlargement of the bacterial cell through increase in mass of the cell components. The DNA material then divides into two equal portions and separate so as to differently attach to the cell membrane. A cell membrane surrounds each of the genetic material. Once surrounded by the membrane, the cell wall curves in across the separated entities and divides the cell into two genetically identical cells. The genetic composition of these new daughter cells is identical to that of the original parent cell. Bacteria which replicate through binary fission are normally susceptible to antibiotics and are less competent in terms of survival compared to those that have undergone genetic mixing and replication.
The other method of reproduction of bacteria is through conjugation. This method is referred to as a kind of sexual reproduction in a sense. The bacterial cells in this case do not divide as the case of binary fission but their genetic material is altered through mixing via contact of two compatible cells that are opposite matches. This is achieved through contact of the involved cells via a pilus, which is carried by the donor cell containing the replicated DNA.
The pilus connects the two cells, the donor and the recipient, and provides a channel of exchange of the genetic material from the former to the latter. The donor donates a portion of the replicated DNA while it retains another portion. Both cells eventually end up with replicated DNA, able to induce conjugation in other cells which are oppositely compatible (without the replicated DNA). Conjugation is a means of transfer of antibiotic resistance between bacteria, which is advantageous to the bacteria but causes havoc in medicine.